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Biomedical subjects

T H Chen

Publications and source records attributed to T H Chen.

At least 127 records · Page 7Linked to original sources
PubMed1993

Expression of an ABA-responsive osmotin-like gene during the induction of freezing tolerance in Solanum commersonii.

We have isolated a cDNA (pA13) of an ABA-responsive gene from suspension cultures of Solanum cultures of Solanum commersonii. The deduced amino acid sequence of pA13 cDNA revealed 89 and 91% identity with tobacco osmotin and tomato NP24 protein, respectively. The accumulation of the transcript corresponding to pA13 cDNA was regulated by ABA, cold temperature, and low water potential treatments. Cold-induced accumulation of the pA13 transcript was partially suppressed by fluridone, an ABA synthesis inhibitor, and the suppression was restored by exogenous ABA application. The transcript corresponding to pA13 also accumulated in an organ-specific manner in response to ABA or cold treatment.

Abscisic Acid↗
PubMed1993

A family of wound-induced genes in Populus shares common features with genes encoding vegetative storage proteins.

Two wound-inducible cDNAs from poplar leaves show sequence identity to vegetative storage proteins (VSP) that accumulate seasonally in poplar bark tissues. We have compared the genomic organization, cDNA sequences and expression of the genes encoding the wound-inducible cDNAs (win4) with that of a bark VSP (called bark storage protein, or BSP). There appear to be several win4 genes in the poplar genome which segregate as a single locus and are therefore likely to be clustered. The same is true of the BSP genes. The win4 locus is linked (map distance of 5 cM) to the BSP locus, consistent with a common evolutionary origin of the genes. A near full-length win4 cDNA shows 75% sequence identity to BSP cDNAs. Both win4 and BSP are systemically wound-inducible; win4 transcripts accumulate in leaves and stems, whereas BSP transcripts accumulate almost exclusively in stems. A phloem transport-dependent signaling mechanism appears to be involved in systemic win4 expression after wounding. In contrast to BSP gene expression, win4 genes are not expressed in response to short day conditions. The data indicate win4 and BSP genes are differentially regulated, and their products may play important roles in the storage and reallocation of nitrogen in perennial plants.

Amino Acid Sequence↗
PubMed1993

Molecular cloning of abscisic acid-responsive mRNAs expressed during the induction of freezing tolerance in bromegrass (Bromus inermis Leyss) suspension culture.

Abscisic acid (ABA) increases the freezing tolerance of bromegrass (Bromus inermis Leyss) cell-suspension cultures at 23 degrees C and elicits many metabolic changes similar to those observed during cold acclimation. Induction and maintenance of freezing tolerance by ABA is accompanied by the expression of novel polypeptides and translatable RNAs. The objective of this study was to isolate and characterize ABA-responsive cDNAs associated with ABA-induced freezing tolerance in bromegrass cell cultures. Among the 16 ABA-responsive cDNA clones isolated, 9 were expressed only with ABA treatment, 7 showed increased transcript level, and 1 was transiently expressed. Cold responsiveness was determined in three clones with increased transcript levels and in the transiently expressed clone. Deacclimation of ABA-hardened cells was a relatively slow process, because all of the novel transcripts persisted for at least 7 d after cells were cultured in ABA-free medium. Preliminary sequencing of cDNAs has identified several clones that share high sequence homology with genes associated with sugar metabolism, osmotic stress, and protease activity. Clone pBGA61 was fully sequenced and tentatively identified as an NADPH-dependent aldose reductase. The predicted amino acid sequence of the coding region shared 92% similarity with that predicted for barley aldose reductase cDNA. It is proposed that expression of genes related to sugar metabolism and osmotic stress may be required for ABA-induced hardening.

Abscisic Acid↗
PubMed1993

Combined therapy of mitomycin C and Chinese medical herbs on experimental liver cancer.

In this research, ICR male mice were chosen for intrahepatic implantation of sarcoma 180 tumor cells (1 x 10(7)). The mice were randomly divided into various groups 24 hours after implantation. One of the groups was the tumor control, the others were singly or combinedly treated with mitomycin C (MMC) and Shih Chuan-Ta-Pu-Tang (SCTPT) or Shi-Hung-One (SHO). The results revealed that the mortality rate (MR60) in the tumor control was 100% and the mean survival time (MST60) was 21.11 +/- 10.69 days. The best therapeutic effect appeared in the group treated with the combination of MMC and SHO, its MR6o was 55.0% and MST 60 was 47.0 +/- 13.4 days.

Animals↗
PubMed1993

Isometric exercise increases strength and does not produce sustained creatinine phosphokinase increases in a patient with polymyositis.

A patient with active stable idiopathic polymyositis received a 4-week supervised right quadriceps and biceps isometric strengthening program. He demonstrated a significant increase in isometric peak torque without a sustained rise in creatinine phosphokinase (CPK). A significant decrease in postexercise CPK occurred at the end of the exercise program. We conclude a randomized clinical trial using a nonexercised patient group vs an exercised patient group may be useful.

Creatine Kinase↗
PubMed1993

Personal competencies and community participation in small community residential programs: a multiple discriminant analysis.

We examined whether broad factors assessing dimensions of personal competency and community participation could be used to discriminate between people with mental retardation who were living in small group homes and small foster homes. Using a large national sample and multiple discriminant analysis procedures, we found that personal competencies were least important in distinguishing on the basis of setting between people living in the two types of residential placements. Primary differences emerged in factors assessing extent of community participation, family relationships, and recreation/leisure integration. Implications for policy and future research were presented and discussed.

Activities of Daily Living↗
PubMed1993

Multiple glomus tumors: a case report.

Multiple glomus tumor (MGT) is rare in incidence. A 37-year-old male was diagnosed to have localized MGT over his right leg. With the characteristics of unusual location (right lower leg), development in sequence, and distribution along the course of the lateral sural cutaneous nerve. Its pathological findings were also characteristic. When the overall presentations showed in cases with recurrent symptoms and signs of glomus tumor after surgical excision, recurrence and multiplicity should be considered.

Adult↗
PubMed1993

Personal characteristics and competence of people with mental retardation living in foster homes and small group homes.

In this 1986-1987 study, the demographic and diagnostic characteristics, problem behaviors, self-care skills, community living skills, domestic expectations, and program goals for personal competence of 336 persons with mental retardation living in a national sample of 181 foster care and small group care settings with 6 or fewer residents was assessed. The findings indicated relatively more severe cognitive impairment among persons in small ICFs-MR, less severe cognitive impairment and fewer functional limitations among non-ICF-MR group home residents, and more functional limitations among residents in foster homes. Neighborhood integration was relatively high for foster home residents, but there were fewer expectations for their development of home and community living skills. Implications for future research and program development in small, community-based residential settings were discussed.

Activities of Daily Living↗
PubMed1992

Skeletal metastasis from occult carcinoma.

We reviewed 177 patients with skeletal metastases, seen between 1984 and 1989, to define the characteristics of metastatic bone disease from an occult primary carcinoma. In 52 (30%) patients, the primary carcinomas could not be identified when the bone metastases were first diagnosed. This group was predominantly male, with intractable pain the most common symptom. The primary tumors were identified on antemortem evaluation in 28 (54%) patients after extensive examination. Among these, the primary tumor was in the lung in 9 patients, followed by liver (8), kidney (5), prostate (3), thyroid gland (2), and rectum (1). The identifiable occult malignancies possessed three common features: all were osteophilic tumors, all had a high incidence in the specific geographic area, and all were not amenable to early detection. The mean survival of these patients was 11 months. Current treatment modalities failed to affect the course of these patients, except for those with primary carcinomas of the kidney and prostate. This observation attests to our limitations in both the diagnosis and treatment of this problem. Efforts should be directed primarily toward excluding those common and/or treatable tumors only.

Bone Neoplasms↗
PubMed1992

Components of personal competence and community integration for persons with mental retardation in small residential programs.

This study identifies components of personal competence and community adjustment in a national sample of persons with mental retardation living in residential facilities of six or fewer residents. Factor analysis of 65 variables yielded an 8 principal component solution that accounted for approximately half the total variance in the observed variables (49%). The eight identified components of personal competence and community adjustment were labeled (1) Self Care and Functional Personal Living Skills, (2) Community Living Skills, (3) Home Living Skills, (4) Problem Behavior, (5) Community Training Goals and Objectives, (6) Recreation/Leisure Activity, (7) Family Contact/Relationships, and (8) Community Assimilation and Acceptance. The implications of reducing potentially hundreds of indicators of personal competence and community adjustment into relatively few broad internally consistent composite constructs are discussed.

Activities of Daily Living↗
PubMed1992

Avascular necrosis of the femoral head--an unusual complication of an intertrochanteric fracture.

Avascular necrosis of the femoral head is an uncommon complication after intertrochanteric fracture. We report six patients with this unusual complication 1-5 years after intertrochanteric fracture. The possible etiologies of this complication include a more proximal intertrochanteric fracture, a high-energy injury with fracture displacement resulting in vascular damage, and adverse influences of the operative procedures on the vascularity of the femoral head.

Adult↗
PubMed1992

Expression of a bacterial ice nucleation gene in plants.

We have introduced an ice nucleation gene (inaZ) from Pseudomonas syringae pv. syringae into Nicotiana tabacum, a freezing-sensitive species, and Solanum commersonii, a freezing-tolerant species. Transformants of both species showed increased ice nucleation activity over untransformed controls. The concentration of ice nuclei detected at -10.5 degrees C in 15 different primary transformants of S. commersonii varied by over 1000-fold, and the most active transformant contained over 100 ice nuclei/mg of tissue. The temperature of the warmest freezing event in plant samples of small mass was increased from approximately -12 degrees C in the untransformed controls to -4 degrees C in inaZ-expressing transformants. The threshold nucleation temperature of samples from transformed plants did not increase appreciably with the mass of the sample. The most abundant protein detected in transgenic plants using immunological probes specific to the inaZ protein exhibited a higher mobility on sodium dodecyl sulfate polyacrylamide gels than the inaZ protein from bacterial sources. However, some protein with a similar mobility to the inaZ protein could be detected. Although the warmest ice nucleation temperature detected in transgenic plants is lower than that conferred by this gene in P. syringae (-2 degrees C), our results demonstrate that the ice nucleation gene of P. syringae can be expressed in plant cells to produce functional ice nuclei.

Journal Article↗
PubMed1992

Complementary DNA cloning of poplar bark storage protein and control of its expression by photoperiod.

Bark storage proteins accumulate in the bark of many woody plants during autumn and winter. In poplar (Populus deltoides Bartr. ex Marsh), the accumulation of the 32-kilodalton bark storage protein is controlled by photoperiod. We have isolated a full-length cDNA encoding for the poplar 32-kilodalton bark storage protein and determined its nucleotide sequence. The derived amino acid sequence shows that poplar bark storage protein is rich in serine, leucine, phenylalanine, and lysine. Poplar bark storage protein is similar to the poplar wound-induced cDNA clone 4 and clone 16 (TJ Parsons, HD Bradshaw, MP Gordon [1989] Proc Natl Acad Sci USA 86: 7895-7899). DNA gel blot analysis suggests that poplar bark storage protein is encoded by a multigene family of about five genes. Poplar plants grown in long days contained low levels of mRNA for the bark storage protein. Exposure to short days resulted in an increase in bark storage protein mRNA within 7 days. After 21 days of short day exposure, high levels of mRNA were detected. The accumulation of bark storage protein mRNA in response to short days was also observed in plants exposed to natural shortening daylengths. Our results indicate that the accumulation of poplar bark storage protein mRNA is controlled by photoperiod. This finding will provide a useful system for investigating photoperiodism in woody plants.

Journal Article↗
PubMed1992

Abscisic Acid increases terrestrial plant cell resistance to hydrostatic pressure.

Cells of the terrestrial plant species bromegrass (Bromus inermis L.) are not naturally adapted to withstand the hydrostatic pressures encountered in aquatic environments. However, after treatment with the natural plant growth hormone abscisic acid (75 micromolar), bromegrass cells survived a hydrostatic pressure of 101.3 megapascals, approximating the limits of ocean depth (10,860 m). The increased resistance to hydrostatic pressure from 1 to 7 days of abscisic acid treatment paralleled the induced elevation of cell tolerance to freezing stress.

Journal Article↗
PubMed1992

Mucolipidoses II and III variants with normal N-acetylglucosamine 1-phosphotransferase activity toward alpha-methylmannoside are due to nonallelic mutations.

Normal N-acetylglucosamine 1-phosphotransferase activity toward mono- and oligosaccharide acceptor substrates was detected in cultured skin fibroblasts from mucolipidoses II and III patients who were designated as variants (one of four mucolipidosis II and three out of six mucolipidosis III patients examined). The activity toward natural lysosomal protein acceptors was absent or deficient in cell preparations from all patients with classical as well as variant forms of mucolipidoses II and III. Complementation analysis, using fused and cocultivated mutant fibroblast combinations, revealed that, while cell lines with variant mucolipidosis III constituted a complementation group distinct from that of classical forms of mucolipidoses II and III, the variant mucolipidosis II cell line belonged to the same complementation group as did the classical forms. In contrast to the mutant enzyme from variant mucolipidosis III patients that failed to recognize lysosomal proteins as the specific acceptor substrates, the activity toward alpha-methylmannoside in the variant mucolipidosis II patient could be inhibited by exogenous lysosomal enzyme preparations (bovine beta-glucuronidase and human hexosaminidase A). These findings suggest that N-acetylglucosamine 1-phosphotransferase is composed of at least two distinct polypeptides: (1) a recognition subunit that is defective in the mucolipidosis III variants and (2) a catalytic subunit that is deficient or altered in the classical forms of mucolipidoses II and III as well as in the mucolipidosis II variant.

Alleles↗
PubMed1992

Coronary artery bypass surgery utilizing right gastroepiploic artery.

Fifteen patients (10 men, 5 women), who underwent coronary artery bypass surgery utilizing the right gastroepiploic artery (R't GEAR) in combination with either the left internal mammary artery (LIMA) or the greater saphenous vein as graft material, were studied. The reasons for utilizing R't GEAR were previous coronary artery bypass operations with resulting marked wound adhesion prohibiting LIMA harvest (five cases), LIMA jeopardized during surgery (three cases), total arterial revascularization using LIMA + R't GEAR (four cases), and near total arterial revascularization using LIMA + R't GEAR + saphenous veins (SV) (three cases). A total of 40 coronary arteries were revascularized: the R't GEAR was used for revascularization of 11 left anterior descending arteries, three right coronary arteries, and one left circumflex artery; LIMA was used for revascularization of four left anterior descending arteries, and three diagonal arteries; the saphenous vein was used for revascularization of eight left circumflex arteries, three diagonal arteries, six posterior descending arteries, and one proximal right coronary artery. There were no hospital mortalities, and follow-up studies revealed satisfactory early results. From our preliminary experience with these 15 cases, we assume that the R't GEAR can be used as the graft material of choice for coronary artery bypass in cases where difficulty in LIMA utilization is encountered or insufficient vein graft conduit is available. It is particularly valuable in reoperations for coronary arterial disease.

Aged↗
PubMed1992

Social integration of older persons with mental retardation in residential facilities.

The findings from a study of the social integration of a national sample of 370 older persons with mental retardation were reviewed. Individuals were selected from a national sample of all facilities owned, operated, or licensed by developmental disabilities agencies having one or more persons 63 years of age or older with mental retardation (N = 235). Facilities included foster care, small group homes (3 to 15 residents), large private facilities, and large state-operated facilities. Information was obtained on resident activities and relations considered to be indicators of social integration through extensive questionnaires completed by primary caregivers. Comparisons of the differences in community integration among residents living in different types of residential facilities were presented. The relative contribution of individual and facility characteristics to the social integration of older persons with mental retardation was explored with hierarchical multiple regression analysis.

Activities of Daily Living↗